This invention relates generally to the setting of alternate time zone data in electronic timepieces. More specifically, the invention simplifies the setting of alternate time zone data by reducing the number of steps which a timepiece operator must complete in order to set the alternate time zone data.
Electronic timepieces which are capable of displaying the time, date and day of the week (DOTW) in multiple time zones are well known in the art. Such timepieces are particularly desirable for those individuals who travel frequently between cities located in different time zones, thus requiring the time, date and DOTW information for more than one time zone. For example, an individual traveling from New York City to Moscow, via Paris, may want to know the time upon his arrival to each destination. Similarly, a businessperson located in New York City may wish to know the time and date information for Paris and Moscow to coordinate business arrangements with foreign associates.
A difficulty encountered with the aforementioned timepieces is that immediately after the initial purchase, or immediately after the timepiece power source has been replaced, numerous procedural steps must be carried out to set the data for each of the multiple time zones. Most often, this means setting all of the data for time, date and DOTW in each time zone. As the number of time zones available in the timepiece increases, the task of setting all of the data for each of the time zones proves cumbersome and increasingly subject to operator error.
Several proposals have been made to improve and simplify the setting of alternate time zone data. For example, U.S. Pat. No. 4,821,248, issued on Apr. 11, 1989, discloses a timepiece having a fundamental (or home) time which may be set to a time other than that of one of a plurality of alternate (or world) time zone times which has been stored in memory. The '248 patent simplifies the setting of a selected one of the plurality of alternate time zone times by interlocking the setting of that world time zone time with the setting of the fundamental time. In accordance with the fundamental time correcting mode of the invention, if the amount by which the fundamental time is to be corrected is greater than a preset time-differential unit (which in the preferred embodiment is thirty minutes), then the time setting of the selected one of the alternate time zones will not be affected by the setting of the fundamental time. However, if the amount by which the fundamental time is to be corrected is less than the preset time-differential unit, the time setting of the selected one of the alternate time zones will be "interlocked" to the fundamental time, and therefore, its setting will be changed simultaneously with that of the fundamental time zone time.
Another proposal, U.S. Pat. No. 4,884,254, issued on Nov, 28, 1989, discloses a time display device having logic means adapted to call up a predetermined number of preselected cities from memory and to display the list on the device's display. Upon selection of one of the preselected cities through operation of an instruction key, the time for the selected city is determined by calling up the time difference corresponding to the selected city (which is itself stored in memory), and then adding it to the current time as outputted from the device's timing means. This selected city is then stored in memory as the first listed city in order to facilitate call-up.
While these inventions simplify the setting of alternate time zones, the setting of each alternate time zone data must still be done on an individual basis. That is, under the '248 patent, only the time setting of one alternate time zone will be "interlocked" when the amount by which the fundamental time is to be corrected is less than the preset time-differential unit. Similarly, under the '254 patent, each alternate time zone time (in the form of a city) must be called-up in order for the timepiece to correct the same. It is therefore one object of the invention to simplify the setting of alternate time zones in an electronic timepiece.
Another object of the invention is to simplify the initial setting of alternate time zones in an electronic timepiece after purchase by a consumer.
Still another object of the invention is to simplify the initial setting of alternate time zones in an electronic timepiece after battery replacement by a user.
An additional object of the invention is to simplify the initial setting of all alternate time zones in an electronic timepiece irrespective of the specific identity of the alternate time zone.